Ventricular assist device

A ventricular assist device (VAD) for use with a heart, comprising:

• a housing;
• an upper membrane pump comprising a pumping chamber coupled to one-way upper inlet and outlet valves, said pumping chamber having a volume between an upper portion of said housing and a membrane sealed to said housing, and an upper connecting rod, one end of which is coupled to a crank pin of a crankshaft and an opposite end of which is coupled to said membrane of said upper membrane pump;
• a lower membrane pump comprising a pumping chamber coupled to one-way lower inlet and outlet valves, said pumping chamber having a volume between a lower portion of said housing and a membrane sealed to said housing, and a lower connecting rod, one end of which is coupled to said crank pin of said crankshaft and an opposite end of which is coupled to said membrane of said lower membrane pump;
• and
• an actuator coupled to said crankshaft configured to rotate said crankshaft and cause said upper membrane pump and said lower membrane pump to alternately draw blood into and pump blood out of their respective pumping chambers, and a control module in operative communication with said actuator, wherein said actuator operates with a pumping frequency which is greater than a pulse frequency of the heart;
• wherein said connecting rod of said upper membrane pump is coupled to a strain relief member which is arranged to press against said membrane of said upper membrane pump, and said connecting rod of said lower membrane pump is coupled to a strain relief member which is arranged to press against said membrane of said lower membrane pump, and wherein for each of said upper and lower membrane pumps, an intermediate member, separate from said strain relief member of each of said upper and lower membrane pumps, is disposed between said strain relief member and said membrane.